Melbourne: On the eve of the Australian Open, Novak Djokovic was asked if he had noticed anything different about Andy Murray.
"He has a shorter haircut," said the five-time Grand Slam winner, smiling.
But then the top-ranked Djokovic turned serious, because Murray's makeover is no joking matter.
The 25-year-old Scot is attempting to win a second consecutive Grand Slam after a breakthrough year that included wins at the London Olympics and the U.S. Open. He arrived in Melbourne with a new demeanor, a sense of calm and confidence that has become a topic of conversation.
"I think mentally something switched in his head," said the top-seeded Djokovic. "And he just started believing much more in his abilities."
"Now that he's done it, he's definitely right up there, one of the first few favorites for any tournament he plays," Djokovic said, as if looking into a crystal ball.
On Wednesday, the third-seeded Murray advanced to the semifinals to take his spot in an all-star lineup featuring the world's top four players.
No. 1 Djokovic has the first semifinal Thursday against No. 4 David Ferrer, who took the spot in the absence of an injured Rafael Nadal.
On Friday, the third-seeded Murray faces No. 2 Roger Federer for the latest rematch in a tight rivalry. Murray leads Federer 10-9 in career matches, including at last year's Olympic final. But he has played the Swiss star in three Grand Slam finals and lost them all.
"I'm expecting a tough match," said Federer, who described Murray as clever and tactical. "He's changed his game around a bit. He's playing more defensive. I'm looking forward to it."
Federer is on a determined roll to win his 18th Grand Slam. The Swiss star stamped his authority on center court by beating the amazingly athletic Jo-Wilfried Tsonga 7-6 (4), 4-6, 7-6 (4), 3-6, 6-3 to reach the Australian Open semifinals for a 10th consecutive year.
After losing, Tsonga picked his favorite to win: "I would say Andy, for the moment. But it could change, of course."
Murray won his quarterfinal against Jeremy Chardy of France 6-4, 6-1, 6-2 to continue a streak of straight-set wins into the semis. Of all the men in the draw, Murray is technically the freshest having spent the least time on court - just under nine hours in the past 10 days.
A visibly shaken Chardy walked into his post-match news conference saying he couldn't believe how well Murray had played.
"I've played him several times, and every time I always thought I had a chance," said the 36th-ranked Frenchman who beat Murray when they last met in August in Cincinnati. "Today he never let me think even once I had a chance to win."
"He's calm on the court," Chardy added. "He was so concentrated, and had so much intensity from the start. Right away I was in difficulty. And during the whole match he never dropped his level."
Murray's intensity on court, diminishes only slightly in his post-match news conferences where he is modest, polite and mild-mannered.
"I thought I did a pretty good job throughout the match," he said, adding that he was pleased to have reached the 12th Grand Slam semifinal of his career. "I can't be disappointed about being in the semis of a slam without dropping a set. That would be silly."
Murray reached the Australian Open semifinals last year, losing to Djokovic. He was twice a finalist in Melbourne in 2011, when he also lost to Djokovic, and runner-up in 2010 to Federer.
Just before arriving in Melbourne last year, Murray teamed up with Ivan Lendl whose coaching has helped produce his added aggressiveness and a new willingness to take chances on court.
Under Lendl's tutelage, Murray made his breakthrough.
He became the first man to win at the Olympics and the U.S. Open in the same year. His win at Flushing Meadows made him the first British man in 76 years to win a Grand Slam - and lifted an enormous burden.
"I kind of maybe always felt like I was having to prove something every time I went on court because I hadn't won a slam," Murray said before the tournament started. "It's nice to not have to worry about that anymore."
After his Wednesday quarterfinal, Murray dismissed comments in the British media that he was upset by having to play all day matches in the hot sun while Federer was given cooler night slots during primetime viewing hours on center court.
"I have no complaints about the schedule at all, and I didn't complain about it the other day," Murray said. "Sometimes it works in your favor and sometimes it doesn't."
The Federer-Tsonga quarterfinal was held Wednesday night at a packed Rod Laver Arena, but instead of studying his next opponent Murray said he planned to practice at a nearby court.
"Tonight, rather than going and watching this match, I'll go out and hit some balls under the lights to be as best prepared as possible."
Asked if he felt prepared to go against his old rivals, Murray replied: "Hopefully, I will go into the matches a little bit calmer than usual, or then I have in the past."